How can i consume HAPI Structure from my spring-boot application

Question

I would like to use the HAPI FHIR structures in my application. My application is a spring-boot application.

Code:

@RequestMapping(value = "{fhirVersion}/$transaction", method = RequestMethod.POST)
    public String execute(@RequestBody Bundle bundle,@PathVariable String fhirVersion) {

    return "";
}

Error:

{
    "timestamp": "2018-04-03T15:06:51.279+0000",
    "status": 415,
    "error": "Unsupported Media Type",
    "message": "Content type 'application/json;charset=UTF-8' not supported",
    "path": "/dstu3/$transaction"
}

Could you please let me know how this could be achieved?

Thanks